Influenza Disease Treatment in Delhi, India

Influenza, commonly known as the flu, is a highly contagious respiratory illness caused by influenza viruses. It affects the nose, throat, and sometimes the lungs, and can range from mild to severe in its severity. Influenza is most commonly observed during winter months, resulting in the possibility of a simultaneous increase in illness among a large number of people, forming an epidemic.

Influenza, commonly known as the flu, is a highly contagious respiratory illness caused by influenza viruses. These viruses can be classified into three main types A, B, and C. These viruses can further be classified into subtypes based on their surface proteins.

• Influenza Virus A: This type of influenza virus is found in both humans and animals, including birds and pigs. Influenza A viruses are further classified into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N). There are 18 different H subtypes and 11 different N subtypes, leading to various combinations. The most common subtypes in humans are H1N1 and H3N2.
• Influenza Virus B: This type is primarily found in humans and is not divided into subtypes. Influenza B viruses can cause seasonal outbreaks and are less prone to major pandemics than influenza A.
• Influenza Virus C: This type of influenza virus also infects humans but typically causes milder respiratory symptoms and is less common. Influenza C does not cause widespread epidemics or pandemics.

Several factors can increase an individual's risk of contracting influenza (flu) and experiencing more severe complications. These risk factors include:

• Age: Infants and young children, as well as individuals aged 65 and older, are more susceptible to severe cases of influenza.
• Health Conditions: People with certain underlying health conditions, such as chronic respiratory diseases (e.g., asthma, COPD), cardiovascular disease, diabetes, and compromised immune systems, are at higher risk of severe influenza outcomes.
• Pregnancy: Pregnant women are at an increased risk of complications from influenza due to changes in the immune system and physiological adaptations during pregnancy.
• Occupational Exposure: Healthcare workers and individuals in occupations with a high risk of exposure to influenza may face an increased likelihood of infection.
• Living Conditions: Crowded living environments, such as long-term care facilities, can facilitate the spread of influenza.
• Travel: International travel, especially to regions with high influenza activity, can elevate the risk of exposure to the virus.
• Compromised Immune Systems: Individuals with weakened immune systems due to medical treatments or certain medical conditions are more vulnerable to severe influenza infections.
• Previous Infection or Vaccination: Lack of prior exposure to certain influenza viruses or failure to receive vaccination can impact an individual's susceptibility to specific strains.
• Social and Economic Factors: Socioeconomic factors, such as limited access to healthcare, crowded living conditions, and inadequate nutrition, can contribute to an increased risk of influenza.
• Behavioural Factors: Certain behaviours, such as not practising good hygiene, not getting vaccinated, and being in close contact with sick individuals, can elevate the risk of influenza transmission.

It's important to recognize these risk factors and take preventive measures, such as annual influenza vaccination, practising good hygiene, and seeking prompt medical attention if symptoms arise, to reduce the risk of influenza and its complications.

Influenza can cause a range of symptoms, which can vary in severity. Common symptoms of influenza include:

• Fever: Influenza often leads to a sudden onset of high fever, which is one of the hallmark symptoms.
• Cough: A persistent cough is a common symptom of influenza. It can be dry or may produce phlegm.
• Sore Throat: Many people with influenza experience a sore or scratchy throat.
• Body Aches and Fatigue: Muscle aches and general fatigue are common with the flu. Individuals may feel overall weakness and exhaustion.
• Headache: Influenza can cause headaches, which may range from mild to severe.
• Chills: People with the flu may experience chills, especially during episodes of fever.
• Runny or Stuffy Nose: Respiratory symptoms, such as a runny or congested nose, are common in influenza.
• Gastrointestinal Symptoms: Some individuals, particularly children, may experience gastrointestinal symptoms such as nausea, vomiting, and diarrhoea.

It's important to note that not everyone with influenza will experience all of these symptoms, and symptoms can vary from person to person. Influenza symptoms typically come on suddenly and can be more severe than those of the common cold

Influenza is often diagnosed based on a combination of clinical symptoms and, in certain cases, laboratory tests. Here are the primary methods used for influenza diagnosis:

Clinical Evaluation

• Doctor's consultation: The first step involves discussing your symptoms, their duration, and any relevant medical history. Your doctor will assess your overall health and perform a physical examination.
• Symptoms analysis: Sudden onset of fever, muscle aches, and extreme fatigue are strong indicators of flu. The presence of other symptoms like sore throat, cough, and runny nose further aids in diagnosis.
• Risk factors: Underlying health conditions, age, and pregnancy can increase susceptibility to influenza and influence diagnosis.

Laboratory Tests

While a clinical evaluation can often be sufficient, laboratory tests can provide definitive confirmation of influenza:

• Rapid influenza diagnostic tests (RIDTs): These are quick (10-15 minutes) point-of-care tests that detect influenza A and B viral antigens in nasal swabs. They are affordable but have lower sensitivity than other tests.
• Molecular assays: Reverse transcription-polymerase chain reaction (RT-PCR) is the gold standard for influenza diagnosis. It detects viral RNA with high accuracy and can differentiate between influenza A and B types.
• Serological tests: These tests measure antibodies against influenza viruses in the blood. They are not commonly used for diagnosis due to delayed results but can be helpful in understanding past exposure or infection.

While influenza often resolves on its own within a few days, proper treatment can alleviate symptoms, shorten the illness duration, and prevent complications. Here's an overview of the various approaches to influenza treatment:

Antiviral Medication

• Oseltamivir (Tamiflu) and Zanamivir (Relenza): These antiviral medications target and inhibit the virus, shortening the duration of illness by 1-2 days if taken within 48 hours of symptom onset. They are particularly recommended for high-risk individuals and those with severe symptoms.
• Baloxavir marboxil (Xofluza): This newer antiviral medication can be taken within 48 hours of symptom onset and is a single-dose treatment.

Additional Supportive Medication

• Cough Suppressants: Over-the-counter cough suppressants can help control a dry, hacking cough. However, consult your doctor before using them, as they can sometimes worsen congestion.
• Decongestants: Nasal decongestants can temporarily relieve a stuffy nose, but use them for a short period and as directed to avoid rebound congestion.
• Antibiotics: Antibiotics are not effective against influenza viruses but might be prescribed if a secondary bacterial infection develops.

• Rest: Getting plenty of sleep helps the body recover and fight off the virus.
• Hydration: Drinking adequate fluids, like water or clear broths, prevents dehydration and maintains essential bodily functions.
• Pain Relief: Over-the-counter pain relievers like acetaminophen or ibuprofen can help manage fever, headaches, and muscle aches.
• Humidifier: Adding moisture to the air can ease a sore throat and cough.
• Warm Compresses: Applying warm compresses to the forehead or chest can provide comfort and relieve aches.

Complications associated with the flu include:

• Pneumonia: The flu is a common precursor to pneumonia, a serious respiratory infection that can cause inflammation in the air sacs of the lungs. This complication can be particularly severe for older adults and individuals with chronic illnesses, posing a risk of fatality.
• Bronchitis: Influenza can lead to bronchitis, characterised by inflammation of the bronchial tubes. This can result in persistent coughing and difficulty breathing.
• Asthma Flare-ups: Individuals with asthma may experience exacerbations of their condition during and after a bout of the flu.
• Heart Problems: In rare cases, the flu has been associated with heart-related complications, including inflammation of the heart muscle (myocarditis) or the lining around the heart (pericarditis).
• Ear Infections: The flu can increase the risk of bacterial infections in the ears (otitis media).
• Acute Respiratory Distress Syndrome (ARDS): Severe cases of the flu may lead to ARDS, a condition characterised by rapid onset of widespread inflammation in the lungs, causing difficulty in breathing.

Pneumonia stands out as one of the most serious complications, especially for older adults and those with chronic illnesses, as it can result in life-threatening consequences. It emphasises the importance of preventive measures, such as annual flu vaccination, to reduce the risk of infection and subsequent complications, particularly in vulnerable populations. Seeking medical attention promptly if symptoms worsen or if there are signs of complications is crucial for effective management of influenza.

Preventing influenza involves a combination of vaccination, practising good hygiene, and adopting lifestyle measures to reduce the risk of infection. Here are key strategies for influenza prevention:

• Vaccination: Get an annual flu vaccine to protect against prevalent strains.
• Hand Hygiene: Wash hands frequently with soap and water, or use hand sanitizer.
• Respiratory Etiquette: Cover mouth and nose when coughing or sneezing, and dispose of tissues properly.
• Avoid Close Contact: Minimise contact with sick individuals and practise social distancing in crowded places.
• Clean Surfaces: Regularly clean and disinfect frequently touched surfaces.
• Healthy Lifestyle: Maintain a balanced diet, get adequate sleep, and engage in regular exercise
• Stay Informed: Follow public health guidelines and recommendations.
• Priority Vaccination: High-risk individuals, including young children and the elderly, should prioritise flu vaccination.

How manageable is influenza with treatment?

While there's no cure for influenza, treatment can significantly manage symptoms and shorten the duration of illness. Antiviral medications like Tamiflu and Relenza, taken within 48 hours of symptom onset, can decrease illness duration by 1-2 days. Supportive measures like rest, hydration, pain relievers, and home remedies like a humidifier can also provide significant relief. However, in some cases, complications can develop, necessitating medical attention.

Is it easy to catch the flu from someone who has it?

Yes, the flu is highly contagious. You can catch it through:

• Respiratory droplets: When an infected person coughs, sneezes, or talks, tiny droplets containing the virus are expelled and inhaled by others.

• Touching contaminated surfaces: The virus can survive on surfaces for several hours. If you touch a contaminated surface and then touch your face, you can become infected.

After being exposed to the flu, how long until I might feel sick?

The incubation period for influenza is typically 1-4 days. This means that after exposure to the virus, it can take 1 to 4 days for symptoms to develop.

Is medical attention necessary for all cases of influenza, or can some recover on their own?

While most healthy individuals recover on their own, medical attention is crucial for certain groups:

• Young children (under 5 years old)
• Older adults (65 years and older)
• Pregnant women
• People with chronic health conditions (e.g., asthma, heart disease, diabetes)
• Individuals with weakened immune systems

How long does someone remain contagious after contracting the flu?

People with influenza are considered contagious from 1 day before symptoms appear until at least 5 days after symptom onset. In some cases, they may be contagious for longer, particularly young children and individuals with weakened immune systems.

What are the key differences between the flu and a common cold?

• Onset: Flu symptoms typically come on suddenly and intensely, while a cold develops gradually.

• Fever: High fever (often above 100°F) is more common with the flu than a cold.

• Muscle aches: Aching muscles, particularly in the back and legs, are a hallmark of influenza but less frequent in colds.

• Duration: Flu symptoms usually last 3-5 days, while colds often linger for 7-10 days.

Is "stomach flu" actually the same as influenza?

No, the term "stomach flu" often refers to gastroenteritis, which is caused by viruses or bacteria affecting the digestive system. It can cause nausea, vomiting, diarrhoea, and abdominal cramps, but unlike influenza, it does not affect the respiratory system.

What are the most effective ways to prevent myself from getting the flu?

• Annual vaccination: The single most effective way to prevent influenza and its complications.
• Frequent handwashing: With soap and water, especially after being in public places or around sick people.
• Avoiding close contact with sick people: Maintain a safe distance and avoid sharing utensils or personal items.
• Covering your cough or sneeze: Use a tissue or your elbow to prevent spreading the virus.
• Maintaining good hygiene habits: Avoid touching your face with unwashed hands.

What is antigenic drift and antigenic shift?

The influenza viruses can undergo changes through two main processes: antigenic drift and antigenic shift.

• Antigenic drift: This is a gradual, natural change in the viral surface proteins (H and N) that occurs over time. It leads to the development of new strains of the virus, contributing to seasonal flu outbreaks.
• Antigenic shift: This is a more abrupt and significant change that occurs when two different influenza A viruses infect the same host cell. This process can lead to the emergence of a new subtype that has a combination of surface proteins not previously seen in human influenza viruses. Antigenic shift has the potential to cause pandemics because the human population has little to no immunity to the new subtype.

Reviewed By Dr. Meenakshi Jain, Director - Internal Medicine on 16 May 2024.